In the basic ceramic block filter design, the resonators are formed by typically cylindrical passages, called resonator cavities (e.g., through-holes), extending through the block from the long narrow side to the opposite long narrow side. The block is substantially plated with a conductive material (e.g., metallized) on all but one of its six (outer) sides and on the inside walls formed by the resonator cavities. One of the two opposing sides containing resonator cavity openings is not fully metallized, but instead bears a metallization pattern designed to couple input and output signals through the series of resonator cavities. This patterned side is conventionally labeled as the top of the block. In some designs, the pattern may extend to sides of the block, where input/output electrodes are formed. Ceramic filter performance is limited by electromagnetic losses due to many factors.